Process scheduling - how does it work.

[Dan O'Neill]

When running a cpu intensive program, we have noticed that after a
while the kernel will renice the process to a lower priority.  This
occurs even when no other user programs are running.

At first this phenomena was thought to occur because some background
system process needed cpu time to perform some utilitarian task.
However, the priority of our program never seems to recover to its
original state and continues to run slow.

I could use some enlightenment in the area of process scheduling and
priority under Ultrix.

This occurs on all our Ultrix machines, but for the sake of clarity,
here is a specific system configuration:

	DECstation 3100, 24Meg of ram, 150Meg swap
	1 RZ23 disk, 1 Rz55 disk
	User files are nfs mounted from a VAX3600 server.
	OS resides locally on the RZ55.

Thanks.

-- 
Dan O'Neill	dan at asihub.uucp    {uunet|ncr-sd}!asihub!dan
Automated Systems, Inc.  San Diego R&D